The present disclosure relates to an image processing apparatus, an image processing method, and a program, and more particularly, to an image processing apparatus, an image processing method, and a program capable of reducing jaggies occurring in an image.
For example, when an image captured by a camera is printed out or is displayed, the image contour of an output object is different from the contour of the original object. That is, the image contour of the output object is output as a step-like saw-toothed contour in some cases.
The step-like saw-toothed shape is generally called jaggies. The jaggies are a kind of aliasing noise. Various image processing methods of reducing the jaggies have hitherto been suggested.
For example, Japanese Unexamined Patent Application Publication No. 2010-67272 discloses a method of reducing the jaggies by determining a direction in which edge detection is performed and by increasing the weight of a smoothing component in a direction further parallel to the edge and performing a blending process in each direction.
However, this method has a problem in that a resolution may deteriorate since the smoothing is performed between the pixels deviated from each other in a direction perpendicular to the edge in a sub-pixel unit when edge preservation smoothing is performed using pixels deviated in its centroid.
Further, Japanese Unexamined Patent Application Publication No. 2009-070123 discloses a method of suppressing the emphasis of the jaggies by allowing an image with a low resolution to have a high resolution near an edge through a high-resolution process.
However, a problem may arise in that the amount of calculation is generally considerable in the high-resolution process and realization is difficult by a small-sized circuit.
Furthermore, Japanese Unexamined Patent Application Publication No. 2004-234623 discloses a method of generating a high-quality image in which the jaggies are reduced by matching and superimposing the positions of the continuously captured images.
In this method, however, a problem may arise in that an edge becomes vague even when the matched positions are slightly deviated from each other, and thus the resolution deteriorates.
Moreover, a problem may also arise in that it is difficult to accurately calculate the position deviation between the images in consideration of both global motion serving as motion information of an entire image and local motion serving as partial motion information and it is difficult to improve the resolution in the whole region of the image.